;------------------------------------------------------------------------------ | |
; | |
; Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR> | |
; SPDX-License-Identifier: BSD-2-Clause-Patent | |
; | |
; Module Name: | |
; | |
; RdRand.nasm | |
; | |
; Abstract: | |
; | |
; Generates random number through CPU RdRand instruction under 64-bit platform. | |
; | |
; Notes: | |
; | |
;------------------------------------------------------------------------------ | |
DEFAULT REL | |
SECTION .text | |
;------------------------------------------------------------------------------ | |
; Generates a 16 bit random number through RDRAND instruction. | |
; Return TRUE if Rand generated successfully, or FALSE if not. | |
; | |
; BOOLEAN EFIAPI InternalX86RdRand16 (UINT16 *Rand); | |
;------------------------------------------------------------------------------ | |
global ASM_PFX(InternalX86RdRand16) | |
ASM_PFX(InternalX86RdRand16): | |
; rdrand ax ; generate a 16 bit RN into eax, | |
; CF=1 if RN generated ok, otherwise CF=0 | |
db 0xf, 0xc7, 0xf0 ; rdrand r16: "0f c7 /6 ModRM:r/m(w)" | |
jc rn16_ok ; jmp if CF=1 | |
xor rax, rax ; reg=0 if CF=0 | |
ret ; return with failure status | |
rn16_ok: | |
mov [rcx], ax | |
mov rax, 1 | |
ret | |
;------------------------------------------------------------------------------ | |
; Generates a 32 bit random number through RDRAND instruction. | |
; Return TRUE if Rand generated successfully, or FALSE if not. | |
; | |
; BOOLEAN EFIAPI InternalX86RdRand32 (UINT32 *Rand); | |
;------------------------------------------------------------------------------ | |
global ASM_PFX(InternalX86RdRand32) | |
ASM_PFX(InternalX86RdRand32): | |
; rdrand eax ; generate a 32 bit RN into eax, | |
; CF=1 if RN generated ok, otherwise CF=0 | |
db 0xf, 0xc7, 0xf0 ; rdrand r32: "0f c7 /6 ModRM:r/m(w)" | |
jc rn32_ok ; jmp if CF=1 | |
xor rax, rax ; reg=0 if CF=0 | |
ret ; return with failure status | |
rn32_ok: | |
mov [rcx], eax | |
mov rax, 1 | |
ret | |
;------------------------------------------------------------------------------ | |
; Generates a 64 bit random number through one RDRAND instruction. | |
; Return TRUE if Rand generated successfully, or FALSE if not. | |
; | |
; BOOLEAN EFIAPI InternalX86RdRand64 (UINT64 *Random); | |
;------------------------------------------------------------------------------ | |
global ASM_PFX(InternalX86RdRand64) | |
ASM_PFX(InternalX86RdRand64): | |
; rdrand rax ; generate a 64 bit RN into rax, | |
; CF=1 if RN generated ok, otherwise CF=0 | |
db 0x48, 0xf, 0xc7, 0xf0 ; rdrand r64: "REX.W + 0f c7 /6 ModRM:r/m(w)" | |
jc rn64_ok ; jmp if CF=1 | |
xor rax, rax ; reg=0 if CF=0 | |
ret ; return with failure status | |
rn64_ok: | |
mov [rcx], rax | |
mov rax, 1 | |
ret | |